1. Field of the Invention
The present invention relates to operations in a wellbore associated with the production of hydrocarbons. More specifically, the invention relates to a system and method for reducing or preventing the occurrence of liquid loading in a natural gas wellbore.
2. Description of the Related Art
Often when natural gas is produced in a wellbore, condensation of liquids occurs as the natural gas expands within the wellbore and cools in transit to the surface. Free liquids such as oil and water in a geologic reservoir may also enter a wellbore along with the natural gas being produced. Initially, the natural gas stream in transit to the surface may carry these liquids up-hole by viscous drag forces. However, as reservoir pressure depletes in mature wellbores, the velocity of the gas stream is often reduced below a “critical velocity” that is required to carry the liquids to the surface. Thus, below the critical velocity, liquids begin to accumulate in the wellbore in a phenomena called “liquid loading.” Liquid loading in a wellbore may inhibit the production of natural gas therefrom. For instance, accumulation of liquids increases the flowing bottom hole pressure, which may result in a cessation of production. Additionally, accumulated liquids may interact with an inner lining of production tubing, yielding corrosion and scaling.
Deliquification and liquid-unloading techniques may be employed to remove accumulated liquids from a wellbore. For example, submersible pumping systems may be installed in a wellbore, or techniques such as plunger lifting may be employed wherein a plunger is raised through the tubing of a wellbore to sweep liquids to the surface for removal. Typically, these procedures, which attempt to remove liquid that has already accumulated in a wellbore, are associated with relatively high operating costs and often require temporarily shutting down, or cycling the wellbore.